Inputs in the Production of Early Childhood Human Capital: Evidence from Head Start

A study conducted by Christopher Walters finds that Head Start centers offering full-day service boost cognitive skills more than other centers, while Head Start centers offering frequent home visiting are especially effective at raising non-cognitive skills. Other key inputs, including the High/Scope curriculum, teacher education and certification, and class size, are not associated with increased effectiveness in Head Start. Together, observed inputs explain a small share of the variation in Head Start effectiveness.

Studies of small-scale “model” early-childhood programs show that high-quality preschool can have transformative effects on human capital and economic outcomes. Evidence on the Head Start program is more mixed. Inputs and practices vary widely across Head Start centers, however, and little is known about variation in effectiveness within Head Start. This paper uses data from a multi-site randomized evaluation to quantify and explain variation in effectiveness across Head Start childcare centers. Walters answer two questions: (1) How much do short-run effects vary across Head Start centers? and (2) To what extent do inputs and practices explain this variation? To answer the first question, the author develops a random coefficients sample selection model that quantifies heterogeneity in Head Start effects, accounting for non-compliance with experimental assignments. Empirical Bayes estimates of the model show that the cross-center standard deviation of cognitive effects is 0.18 test score standard deviations, which is larger than typical estimates of variation in teacher or school effectiveness. Next, the author assess the role of inputs in generating this variation, focusing on inputs commonly cited as central to the success of model programs.